Alpha-1A adrenergic receptor

The alpha-1A adrenergic receptor (α_1A adrenoreceptor), also known as ADRA1A, formerly known as the alpha-1C adrenergic receptor, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.

Receptor

There are 3 alpha-1 adrenergic receptor subtypes: alpha-1A, -1B and -1D, all of which signal through the Gq/11 family of G-proteins. Different subtypes show different patterns of activation. The majority of alpha-1 receptors are directed toward the function of epinephrine, a hormone that has to do with the fight-or-flight response.

Gene

This gene encodes the alpha-1A-adrenergic receptor. Alternative splicing of this gene generates four transcript variants, which encode four different isoforms with distinct C-termini but having similar ligand binding properties.

Ligands

Agonists

• 6-(5-fluoro-2-pyrimidin-5-yl-phenyl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazole: EC₅₀ = 1nM, E_max = 65%; good selectivity over α1B, α1D and α2A subtypes
• further partial agonistic imidazole compounds
• A-61603

Antagonists

• Tamsulosin: for treatment of benign prostatic hyperplasia
• Silodosin: for treatment of benign prostatic hyperplasia
• Risperidone
• WB-4101
• Ziprasidone

Role in neural circuits

α1A-adrenergic receptor subtypes increase inhibition at dendrodendritic synapses, suggesting a synaptic mechanism for noradrenergic modulation of olfactory driven behaviors.

See also

• Adrenergic receptor